Power-distributing system



8 HEIJI vosl-nzAw WISH-DISTRIBUTING SYSTEM [F1106 Au 31, 1966 United States Patent Office 3,416,311 POWER-DISTRIBUTING SYSTEM Heiji Yoshizawa, Komatsu-shi, Japan, assignor to Kabushiki Kaisha Kornatsu Seisakusho (Komatsu Mfg. Co. Ltd.), Tokyo, Japan Filed Aug. 31, 1966, Ser. No. 576,369 Claims priority, application Japan, Sept. 7, 1965, 40/ 54,381 Claims. (CI. 6053) ABSTRACT OF THE DISCLOSURE A system for distributing power among a plurality of hydraulic circuits of a hydraulic transmission. Each hydraulic circuit includes a pump and a motor hydraulically connected to the pump through a pair of conduits with the output of the motor of each circuit being connected to an element which is to be driven. Each hydraulic circuit further includes a shorting means for shorting the flow of fluid between the conduits of each circuit. A totalizing means is operatively connected with the plurality of hydraulic circuits for totalizing the powers respectively expended in the plurality of circuits at any given moment, and this totalizing means is also operatively connected with the plurality of shorting means of the several hydraulic circuits, respectively, for simultaneously actuating all of the shorting means to place them simultaneously in shorting positions where the conduits of each circuit have the flow of fluid shorted therebetween, this totalizing means bringing about the simultaneous actuation of all of the shorting means when the sum of the powers expended at any given instant in all of the hydraulic circuits exceeds a given value. The several pumps of the several circuits are driven from a Single source of power capable of efliciently supplying power up this latter given value, so that power from a single source can be distributed in any desired manner among the several hydraulic circuits as long as the total power of all of the circuits does not exceed the value at which the totalizing means will shift the plurality of shorting means to their shorting positions.

This invention relates to improvements in speed changing method for a hydraulic transmission and particularly to means for making an output of an engine constant.

It is well known that a pair of speed changers for the hydraulic transmission comprise a pair of variable output pumps and a pair of variable output motors. The motor is driven by an oil discharged from the pump which is driven by a single engine. The function of the hydraulically driven speed changer is achieved by varying the output of either the pump or the motor. The highest pressure for the circuit is limited by a pressure governing valve depending upon a strength of the device and the efliciency thereof. When the pump output pressure is elevated up to this highest pressure, it is probable that the engine does not restart by virtue of a shortage in output of the engine. A counter-measure in accordance with the prior art for preventing an engine from such a difficulty in restarting consists in preliminarily dividing the output of the engine equally into half for each of the pair of the speed changer in which the highest pressure for each pump output is controlled. This system may be formulated as follows:

P /zP 2) P /zP and 3,416,31 1 Patented Dec. 17, 1968 left speed changer, and P represents the output of the engine. As seen from these formulas, only at highest a half of the output of the engine may be consumed by either speed changer. For example, when the left speed changer is fully loaded while the right speed changer is not loaded at all, only a half of the engine output is utilized. Particularly, in case of a tractor which is apt to be loaded unequally for both driving wheels by virtue of frequent turnings and irregular land, if controlled as above, more than a half of the engine is probably required for one side, resulting in that the other side becomes short in power and, in turn, the output of the engine is not used effectively.

The primary object of this invention is to provide a speed changing means for a hydraulic transmission in which an output of an engine is made constant and which enables use of the output up to the maximum. Such an ideal state may be formulated as follows:

P +P P Another object of this invention is to provide a speed changing means for a hydraulic transmission which prevents an engine from having difliculty in restarting.

Briefly stated in accordance with one aspect of this invention, there is provided a speed changing means for a hydraulic transmission in which a liquid pressured by a pair of pumps driven by a single engine is introduced into a pair of motors which drive a pair of driving wheels, respectively, and in which output pressures of the liquid being introduced into the pair of motors are detected as a sum of moments acted on points on levers, with the distance from said points to fulcrums of the levers corresponding to the outputs, the sum being compared with a moment which corresponds to the maximum output of the engine and is detected similarly to the above moments, and the high pressure side is shorted with the low pressure side between the pair of pumps and the pair of motors, respectively, in such a manner that the sum does not exceed the last-named moment, whereby the speeds of the motors are changed individually while the engine is kept from a shortage of output.

The invention will be better understood and other objects and additional advantages of the invention will become apparent upon perusal of the following description taken in connection with the drawings, in which:

FIG. 1 is a hydraulic circuit diagram of a hydraulic transmission in accordance with this invention;

FIG. 2 is a diagrammatic side view of a speed changing means for the hydraulic transmission in accordance with this invention;

FIG. 3 is a and FIGS. 4 and 5 are diagrams for explaining the operation thereof.

Referring more particularly to the drawings, the preferred embodiment of this invention will now be described; however, this description will be understood to be illustrative of the invention and not as limiting it to the particular construction as shown and described. There are a pair of hydraulic circuits as shown in FIG. 1, in which a speed changing means is used, and which comprises a pair of highest pressure controlling valves 1, a pair of high pressure charging valves 2, a pair of shorting valves 3, and a constant output mechanism 4.

Outputs of a pair of pumps PV and P'V', which are determined depending upon the capacities of the pumps and operations by means of a pair of operating levers 11 and 11;,, are charged into the constant output mecha nism 4, through the pair of high pressure charging valves 2, respectively. When a sum of powers consumed by the pair of pumps become in excess of the output of the engine ENG, the constant output mechanism 4 acts so as partly diagrammatic front view thereof;

perpendicularly to the axes thereof, respectively, at the same time they are axially displaceable within the cylinders and are connected to piston rods the free ends of which press against the lever arms 31;, and 31 in the same way that the bottoms of the cylinders 30 and 30 bear against these lever arms in FIGS. 2-4. The arms 31 and 31;, are fixed to a common arm 32 which carries a single roller 36, but for the schematic illustration of FIG. 5 a pair of such arms are shown with a pair of rollers 36, and the spring 39 is shown in FIG. 5 as 'a spring which is under tension urging the piston assembly 38 to the left, as viewed in FIG. 5, against the roller assembly 36. Thus, with this construction also the single arm which carries the single roller 36 will act on the piston 38 in opposition to the spring 39 for bringing about actuation of the shorting means 3 when the total of the powers of the several circuits exceeds a given value.

As has been indicated above, the charging valve assemblies 2 of the several hydraulic circuits are respectively in communication with the totalizing means 4 for introducing the outputs of the pumps of the several circuits into the mechanism 4. Referring to the actual details shown on the one hand in FIGS. 2-4 and on the other hand in FIG. 5, the charging valve assemblies 2 respectively communicate with the cylinders 30 and 30 for supplying the latter, beneath the pistons 29, as viewed in FIG. 2, with the pressured output of the pumps, respectively, so as to urge the cylinders schematically represented in FIGS. 24 downwardly respectively into engagement with the lever arms 31;; and 31 while in the embodiment of FIG. 5 the charging valve assemblies 2 also direct the pressured output from the pumps respectively into the cylinders 30 and 30 but with the schematic illustration of FIG. 5 it is to be understood that the pressured fluid acts downwardly on the piston 29 and upwardly on the piston 29;, although in the actual construction both of these pistons are acted upon to be urged in the same direction by the pressured fluid so as to urge the pair of parallel arms of the bell crank to turn in a direction which will cause the single arm 32 of the bell crank to press against the piston 38 in opposition to the force of the spring 39.

It will thus be seen that with the structure of the invention there are a plurality of hydraulic circuits, the embodiment of FIG. 1 being provided with two such circuits, each of which includes a pump and motor hydraulically interconnected with each other through the high and low pressure conduits of each circuit. Each hydraulic circuit further includes a shorting means 3 capable of being displaced to a shorting position providing direct communication between the high and low pressure conduits of each circuit but being out of its shorting position during normal operations of the several circuits. Through the above-referred-to charging valve assemblies 2 the totalizing means 4 is in communication with the several hydraulic circuits for totalizing the powers respectively expended at the several circuits at any given instant. As is apparent from the above description, this totalizing means 4 includes the several cylinder-and-piston assemblies such as the assemblies 29 30 and 29 30 with each of these assemblies having a cylinder member and a coacting piston member. One of the latter members is urged by the pressured output of the pump of the particular hydraulic circuit against an arm of a bell crank means which includes a plurality of arms respectively acted upon by the several piston-and-cylinder means which receive the pressured output from the pumps of the several hydraulic circuits, respectively, and all of these latter arms of the bell crank means are connected with a common output bell crank arm which thus totals the several powers of the circuits and applies the total power to the piston 38 in opposition to the spring 39 of the totalizing means 4, so that the latter will, when a given total power value is exceeded, simultaneously actuate all of the shorting means 3 to cause each circuit to have the fluid shorted between its high and low pressure conduits. Of course, the total power at which the totalizing means 4 responds to act simultaneously upon all of the shorting means corresponds to the total power which can be supplied from the single source of energy such as the engine indicated schematically at the left of FIG. 1 and operatively connected to all of the pumps of all of the hydraulic circuits for delivering power thereto. In this way it becomes possible to have any desired distribution of the power available from the single source among the several hydraulic circuits including, for example, all of the power to one of the circuits with none of the power going to any of the other circuits, and the operations will be maintained without interruption as long as the total of the powers expended at any given instant at the several hydraulic circuits does not exceed that which is supplied by the engine or other single source of energy.

While particular embodiments of this invention have been illustrated and described, modifications thereof will readily occur to those skilled in the art. It should be understood therefore that the invention is not limited to the particular method and arrangement disclosed but that the appended claims are intended to cover all modifications which do not depart from the true spirit and scope of the invention.

What is claimed as new and desired -to be secured by Letters Patent of the United States is:

1. In a power-distributing system, a plurality of hydraulic circuits each of which includes a pump and a motor driven thereby and communicating therewith through a pair of conduits, each circuit also including a shorting means extending between said pair of con duits thereof and having a normally non-shorting position and a shorting position shorting the flow of fluid between said conduits, and totalizing means communicating with all of said circuits for totalizing all of the powers respectively expended thereby at any given instant, said totalizing means also being operatively connected with the plurality of shorting means of said circuits for simultaneously placing all of said shorting means in their shorting positions when the power totalized by said totalizing means exceeds a given value.

2. The combination of claim 1 and wherein the pump and motor of each circuit are reversible, and charging means interposed between said totalizing means and each circuit for charging said totalizing means with the pressured fluid of each circuit irrespective of the direction of operation of the pump and motor of each circuit.

3. The combination of claim 1 and wherein a single source of power is operatively connected with the pumps of the several circuits for driving said pumps.

4. The combination of claim 3 and wherein the power value at which said totalizing means responds for actuating said plurality of shorting means corresponds to the maximum power which can be supplied from said source of power to the several pumps of said plurality of circuits, respectively.

5. The combination of claim 4 and wherein there are only two circuits with the motors thereof operatively connected to elements such as tractor-driving elements for operating the latter.

6. The combination of claim 1 and wherein a plurality of pump-control means are provided for respectively controlling the pumps of the several circuits, said totalizing means including a plurality of pressure-responsive means for said circuits, respectively, supplied with the pressured output of said circuits, respectively, said plurality of pump-control means respectively displacing said pressure-responsive means through distances from a given axis corresponding to the operations of said plurality of pump means provided by said plurality of pumpcontrol means, respectively, and said totalizing means including a lever means turnable about the latter axis and acted upon by said plurality of pressure-responsive means with lever arms, respectively, corresponding to mild mechanical treatment may, for instance, consist of striking, rubbing, brushing, or vibrating. Such treatment during the electrical treatment will not only fold out but also spread the material out.

At this point in the flow sheet of FIGURE 1 the sheet material is in a spread-out condition wherein the individual fibrils, making up the material, are parallel to the longitudinally axis of the sheet material. In many cases, and for many applications, this is a desirable configuration. However, for certain textile products the yarn used in the manufacture therein should not be lean and smooth but rather should have a high percentage of loose-fibrils along the surface of the web or sheet as the case may be. For instance, in the case of blankets, carpets, and fabrics made from woolen yarns, it is essential to use a bulky yarn which is not produced under the process described in the above-identified patent.

My invention resides in forming a pile fabric from this polymeric sheet material as it emerges from the foldingout step.

With reference to FIGURES 2 and 3, after the sheet material has been folded out as described hereinabove, it passes between a pair of generally cylindrical rollers 12 and 13, which are rotatably mounted in frame plates 14 and 16 respectively. These frame plates 14 and 16 extend vertically from a base plate 18 which is mounted on wheels 20. This unit is able to be wheeled into a position to receive the film 10 directly from the folding-out step described in FIGURE 1 in the event that it is desirable to make the whole process continuous. The sheet or web 10 passes from the rollers 12 and 13 to a roller 54 (see FIGURE 6) which is also rotatably mounted in plates 14 and 16.

With reference to FIGURE 6, a plurality of rollers 54 are shaped to form a crown 56 at their centers. As a result, the fibrils in the central portion of film 10 passing over the crown 56 will break while those in the edge portion of the film passing over the edge of the roller will not. This action of crowned rollers 54 (FIGURE 2) causes the fibrils in the center portion of sheet 10 to break. This web is particularly useful in making yarn and as such it is twisted by conventional yarn twisting means as it is wound onto a spool 58.

As shown in FIGURES 2 and 3, rollers 13, 54 (only one roller is shown; however, it would be within the skill of the art to connect a plurality of crowned rollers into the mechanism) and 29 are connected to a suitable driving mechanism 30. This mechanism comprises an endless belt or chain 32 which passes over a pulley or sprocket 34 which is fixed to roller 54, then over a sprocket 36 which is fixed to roller 13, then over a sprocket 38 which is fixed to roller 29, then over an idler sprocket 40, then over a drive sprocket 42, which is driven by any suitable power source such as electric motor 44, and finally back over sprocket 34. The rollers 12, 13, 54, 28, and 29 are rotated in the directions shown by the arrows.

With reference to FIGURE 4, roller 22 is provided with a plurality of grooves 24 and a plurality of needles 26- or other similar sharp, pointed implements, which project radially from the center of the grooves 24. These needles may be secured in the grooves 24 in any suitable manner. As the sheet 10 passes over the roller 22, portions of it are channelled into the grooves 24 and become impaled upon the needles which penetrate through the sheet material and cause a portion of the individual fibrils to be severed. The degree of breakage would be determined by the number of grooves in the roller and the number of pins in the grooves; however, no more than one-half of the fibers passing over the roller should be broken in order to retain sufiicient web strength. In the preferred embodiment we show only one roller but it would be within the skill of the art to adapt a plurality of rollers over which the film could be passed. The film after passing over the pin-studded roller 22 is received by a pair of pick-up rollers 28 and 29 which are also rotatably mounted in the frame plates 14 and 16. These rollers feed the bulky sheet material to a suitable take-up mandrel (not shown).

FIGURE 5 illustrates another embodiment of my invention. In this embodiment a roller 46 contains a plurality of grooves 48 around the perimeter thereof. These grooves are cut at an angle of 45 to the horizontal axis 50 of the roller 46. This roller 46 is attached to frames 14 and 16 in place of roller 22. A plurality of knife blades 52 are positioned around the circumference of roller 53 rotatably mounted between the vertical frames 14 and 16 a predetermined distance from roller 46. The sheet 10 is passed between the roller and the blade. The blade 52 is rotated in close enough proximity to the roller 46 so that portions of the film 10 pass over the crown of the grooves 48 and are cut by the rotating blades 52. Because of the angle of inclination of these grooves a discontinuous chopping of the individual fibrils results without cutting entirely across the sheet itself. The strength of the sheet itself is not significantly affected. This fabric possesses a tremendous advantage over a normal pile fabric because the pile fibers form an integral part of the sheet and are firmly anchored to the surface of the sheet.

In order to illustrate with greater particularity and clarity the operation of my process, the following examples are offered as illustrative of the operation thereof. The specific materials and conditions given in the examples are presented as being typical and should not be construed to limit my invention unduly.

EXAMPLE I A 60-inch wide fibrillated web of 0.8 mil polyethylene, having a density of 0.95 gram/cc. and a melt index of 0.3 (ASTM D 123 8-5DT, Condition E), is threaded through the machine described in FIGURE 2. A chopper roller 53 is provided with 12 tempered spring steel blades 52 around its circumference. The blades 52 coact with a 12-inch diameter grooved roller 46, made of mild steel and coated to a thickness of 60 mils with durometer rubber. Each groove 48 in roller 46 defines an ellipse in a plane making a 45 angle with the roller axis. These grooves are Aa-inch wide, Aa-inch deep, and spaced so that their centers are fli-inch apart, and having all their edges and corners chamfered and rounded on a -inch radius. Bulk film is fed to roller 12 at the rate of 20 feet per minute while the machine is being adjusted to insure clean, uniform cuts. After adjustment, the rate is increased to feet per minute and about 2000 feet of the material is fed through the machine.

Air filters 2 /2 feet square are produced from some of this material by laminating 21 layers of this bulked film together, each layer being laid at right angles to the adjacent layers 21 and being stitched together in both directions across the film at 6-inch intervals with cotton string and subsequently edged with an aluminum channel having a As-inch flange.

In another application ten 8-foot sections of this bulked fibrilated web are stitched together on 4-inch centers both lengthwise and crosswise and the edges bound to make an exceptionally warm, lightweight blanket.

Example 11 The rollers 46 and 53 are replaced with a 12-inch diameter pin-studded roller 22 similar to that shown in FIGURE 4. The grooves 24 are /2-inch center-to-center with a sharp 60 included angle peak between the grooves. In each groove 36 equally spaced cylindrical pins 26 are positioned wherein each pin is 7 -inch in diameter and has a flat, sharp edged top portion located -inch below the peaks. Web material similar to that used in Example I is threaded through the machine and the machine is started and run at an initial rate of about 15 feet per minute output while adjustments of the film tension over the pinstudded roller 22 are made. After adjustment, the rate is increased to 150 feet per minute to produce approximately 

